Cooled ring segment

ABSTRACT

A ring segment for a gas turbine engine includes a panel and a first mating edge cooling system. Cooling fluid is provided to an outer side of the panel and an inner side of the panel defines at least a portion of a hot gas flow path. A cooling system receives a portion of the cooling fluid provided to the outer side and includes at least one impingement chamber. Each impingement chamber includes at least one metering supply passage and at least one metering discharge passage. The metering supply passage(s) extends from the outer side of the panel to the impingement chamber. Cooling fluid impinges on a surface of the panel defining the impingement chamber as it flows therein through the metering supply passage(s). The metering discharge passage(s) extends from the impingement chamber to a first or second mating edge of the panel.

FIELD OF THE INVENTION

The present invention relates to ring segments for gas turbine engines and, more particularly, to cooling of ring segments in gas turbine engines.

BACKGROUND OF THE INVENTION

It is known that the maximum power output of a combustion turbine is achieved by heating the gas flowing through the combustion section to as high a temperature as is feasible. The hot gas, however, heats the various turbine components, such as the combustor and transition ducts, and vanes and ring segments, which it passes when flowing through the turbine section. One aspect limiting the ability to increase the combustion firing temperature is the ability of the turbine components to withstand increased temperatures. Consequently, various cooling methods have been developed to cool turbine hot parts.

In the case of ring segments, ring segments typically may include an impingement tube, also known as an impingement plate, associated with the ring segment and defining a plenum between the impingement tube and the ring segment. The impingement tube may include holes for passage of cooling fluid into the plenum, wherein cooling fluid passing through the holes in the impingement tube may impinge on the outer side of the ring segment to provide impingement cooling to the ring segment. In addition, further cooling structure, such as internal cooling passages, may be formed in the ring segment to facilitate cooling thereof.

SUMMARY OF THE INVENTION

In accordance with an aspect of the invention, a ring segment is provided for a gas turbine engine. The ring segment comprises a panel and a first mating edge cooling system. The panel includes a leading edge, a trailing edge, a first mating edge, a second mating edge, an outer side, and an inner side. Cooling fluid is provided to the outer side of the panel and the inner side of the panel defines at least a portion of a hot gas flow path through the gas turbine engine. The first mating edge cooling system is within the panel and receives a portion of the cooling fluid provided to the outer side of the panel for cooling the panel at one of the first and second mating edges. The first mating edge cooling system comprises at least one first mating edge impingement chamber. Each first mating edge impingement chamber includes at least one metering supply passage and at least one metering discharge passage. The at least one metering supply passage extends from the outer side of the panel to the first mating edge impingement chamber. Cooling fluid impinges on a surface of the panel defining the first mating edge impingement chamber as it flows into the first mating edge impingement chamber through the at least one metering supply passage. The at least one metering discharge passage extends from the first mating edge impingement chamber to the one of the first and second mating edges of the panel.

In accordance with another aspect of the invention, a ring segment is provided for a gas turbine engine. The ring segment comprises a panel, a central recessed portion, recess portion walls, and at least one impingement chamber. The panel includes side edges comprising a leading edge, a trailing edge, a first mating edge, and a second mating edge. The panel further includes an outer side and an inner side, wherein cooling fluid is provided to the outer side and the inner side defines at least a portion of a hot gas flow path through the gas turbine engine. The central recessed portion defines a recessed surface formed in the outer side of the panel and is surrounded by a rim portion comprising an unrecessed portion extending around an outer periphery of the recessed portion along each of the side edges. The recess portion walls define the outer periphery of the recessed portion. Each recess portion wall extends radially between the recessed surface and the unrecessed portion. The at least one impingement chamber is located in the panel and includes at least one metering supply passage extending from the outer side for passage of cooling fluid into the impingement chamber to impinge on and cool a surface of the impingement chamber and at least one metering discharge passage extending from the impingement chamber to one of the side edges for passage of cooling fluid from the impingement chamber to the one side edge.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying Drawing Figures, in which like reference numerals identify like elements, and wherein:

FIG. 1 is cross sectional view of a portion of a turbine section of a gas turbine engine, including a ring segment constructed in accordance with the present invention;

FIG. 2 is a top plan view of the ring segment illustrated in FIG. 1;

FIG. 3 is a cross sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is a cross sectional view taken along line 4-4 in FIG. 2; and

FIG. 5 is a top plan view of a ring segment constructed in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation, a specific preferred embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention.

FIG. 1 illustrates in cross section a portion of a turbine section 10 of a gas turbine engine. Within the turbine section 10 are a series of rows of stationary vanes and rotating blades. In FIG. 1, a single blade 12 forming a row 12 a of blades is illustrated. Also illustrated in FIG. 1 is part of an upstream vane 14 forming a row 14 a of upstream vanes, and part of a downstream vane 16 forming a row 16 a of downstream vanes. The blades 12 are coupled to a disc (not shown) of a rotor assembly. A hot working gas from a combustor (not shown) in the engine flows in a hot gas flow path 20 passing through the turbine section 10. The working gas expands through the turbine 10 and causes the blades 12, and therefore the rotor assembly, to rotate.

In accordance with an aspect of the invention, an outer seal structure 22 is provided about and adjacent the row 12 a of blades. The seal structure 22 comprises a plurality of ring segments 24, which, when positioned side by side in a circumferential direction, define the seal structure 22. The seal structure 22 has a ring shape so as to extend circumferentially about its corresponding row 12 a of blades. A corresponding one of the seal structures 22 may be provided about each row of blades provided in the turbine section 10.

The seal structure 22 comprises an inner wall of a turbine housing in which the rotating blade rows are provided and defines sealing structure for preventing or limiting the working gas from passing through the inner wall and reaching other structure of the turbine housing, such as a blade ring carrier 26 and an associated annular cooling fluid plenum 28. It is noted that the terms “inner”, “outer”, “radial”, “axial”, “circumferential”, and the like, as used herein, are not intended to be limiting with regard to orientation of the elements recited for the present invention.

Referring to FIGS. 2 and 3, a single one of the ring segments 24 of the seal structure 22 is shown. The ring segment 24 comprises a panel 30 including side edges comprising a leading edge 32, a trailing edge 34, a first mating edge 36, and a second mating edge 38. The panel 30 further includes an outer side 40 (FIGS. 1 and 2) and an inner side 42 (FIG. 1), wherein the inner side 42 defines a corresponding portion of the hot gas flow path 20. The panel 30 defines a structural body for the ring segment 24, and includes a plurality of front flanges or hook members 44 a and a plurality of rear flanges or hook members 44 b, see FIGS. 1 and 2. The front and rear hook members 44 a, 44 b are rigidly attached to the panel 30, and may be formed with the panel 30 as an integral casting, or may be formed separately and subsequently rigidly attached to the panel 30. Moreover, if formed separately from the panel 30 the hook members 44 a, 44 b may be formed of the same material or a different material than the panel 30. Each ring segment 24 is mounted within the turbine section 10 via the front hook members 44 a engaging a corresponding structure 46 of the blade ring carrier 26, and the rear hook members 44 b engaging a corresponding structure 48 of the blade ring carrier 26, as seen in FIG. 1.

Referring to FIG. 1, the blade ring carrier 26 defines, in cooperation with an impingement tube 50, also known as an impingement plate, the annular cooling fluid plenum 28, which defines a source of cooling fluid for the ring segment 24, as is described further below. The impingement tube 50 is secured to the blade carrier ring 26 at fore and aft locations 52, 54, as shown in FIG. 1. The cooling fluid plenum 28 receives cooling fluid through a channel 56 formed in the blade ring carrier 26 from a source of cooling fluid, such as bleed air from a compressor (not shown) of the gas turbine engine. As shown in FIG. 1, the impingement tube 50 includes a plurality of impingement holes 58 therein. Cooling fluid in the cooling fluid plenum 28 flows through the impingement holes 58 in the impingement tube 50 and impinges on the outer side 40 of the panel 30 during operation, as will be discussed herein.

Referring to FIGS. 1 and 2, the outer side 40 of the illustrated panel 30 is formed with an indented or central recessed portion 60 defining a recessed surface of the panel 30. The outer side 40 of the panel 30 further comprises a rim portion 62 surrounding the central recessed portion 60. The rim portion 62 comprises an unrecessed portion extending around a periphery of the central recessed portion 60 along each of the side edges, i.e., the leading edge 32, the trailing edge 34, the first mating edge 36, and the second mating edge 38. Recess portion walls 32 a, 34 a, 36 a, 38 a (see FIG. 2) extend at least partially in the radial direction between the recessed surface and the unrecessed portion and define the outer periphery of the central recessed portion 60. It should be noted that the outer side 40 of the panel 30 need not comprise the central recessed portion 60 and the rim portion 62 and may comprise, for example, an area that is substantially entirely planar.

Each ring segment 24 of the seal structure 22 comprises a plurality of cooling systems, each of which will be discussed below. However, the cooling systems of only a single one of the ring segments 24 will be described herein, it being understood that the cooling systems of the remaining ring segments 24 are substantially the same as the cooling systems of the ring segment 24 described.

Referring to FIGS. 2 and 3, the ring segment 24 according to this embodiment includes a trailing edge cooling system 70, a first mating edge cooling system 72, and a second mating edge cooling system 74 formed within the panel 30. It is noted that the ring segment 24 could comprise additional or fewer cooling systems without departing from the spirit and scope of the invention.

The trailing edge cooling system 70 comprises a plurality of metering supply passages 80 formed in the central recessed portion 60 of the panel 30. The metering supply passages 80 of the trailing edge cooling system 70 in the embodiment shown are located toward the leading edge 32 of the panel 30 but could be located elsewhere. The metering supply passages 80 direct a portion of the cooling fluid provided from the cooling fluid plenum 28 to the outer side 40 of the panel 30 into impingement chambers 82 of the trailing edge cooling system 70. As the cooling fluid enters the trailing edge impingement chambers 82 through the metering supply passages 80 it impinges on a surface of the panel 30 that defines the corresponding impingement chamber 82. Sizing of diameters of the trailing edge metering supply passages 80 will be discussed below. While six circumferentially spaced apart trailing edge impingement chambers 82 are illustrated in FIGS. 2 and 3, additional or fewer trailing edge impingement chambers 82 could be provided for the trailing edge cooling system 70.

As shown in FIGS. 2 and 3, the trailing edge impingement chambers 82 comprise an elongated axial dimension extending parallel to the first and second mating edges 36, 38. The axial dimension of the impingement chambers 82 is substantially greater than a circumferential width dimension of the impingement chambers 82 extending generally perpendicular to the first and second mating edges 36, 38.

The trailing edge impingement chambers 82 are each associated with a corresponding discharge passage 84 of the trailing edge cooling system 70. The trailing edge discharge passages 84 extend from the respective trailing edge impingement chambers 82 to the trailing edge 34 of the panel 30 for discharging cooling fluid from the trailing edge impingement chambers 82.

As shown in FIGS. 2 and 3, the first and second mating edge cooling systems 72, 74 each comprise a plurality of metering supply passages 90, 92 formed in the rim portion 62 of the panel 30. The metering supply passages 90 of the first mating edge cooling system 72 in the embodiment shown are located toward the first mating edge 36 of the panel 30, see also FIG. 4. The first mating edge metering supply passages 90 direct a portion of the cooling fluid provided from the cooling fluid plenum 28 to the outer side 40 of the panel 30 into a single impingement chamber 94 of the first mating edge cooling system 72. The metering supply passages 92 of the second mating edge cooling system 74 in the embodiment shown are located toward the second mating edge 38 of the panel 30. The second mating edge metering supply passages 92 direct a portion of the cooling fluid provided from the cooling fluid plenum 28 to the outer side 40 of the panel 30 into a single impingement chamber 96 of the second mating edge cooling system 74. Sizing of diameters of the first and second mating edge metering supply passages 90, 92 will be discussed below.

As the cooling fluid enters the first and second mating edge impingement chambers 94, 96 through the respective metering supply passages 90, 92 it impinges on surfaces of the panel 30 that define the respective first and second mating edge impingement chambers 94, 96. Due to the location and spacing of the metering supply passages 90, 92, impingement cooling is provided across a substantial area of the panel 30 near the respective first and second mating edges 36, 38 of the panel 30. While the first and second mating edge impingement chambers 94, 96 are illustrated in FIGS. 2 and 3 as comprising single chambers, additional first and second mating edge impingement chambers 94, 96 could be provided, e.g., as shown in the embodiment illustrated in FIG. 5 to be discussed below.

As shown in FIGS. 2 and 3, the first and second mating edge impingement chambers 94, 96 comprise elongated axial dimensions extending parallel to the first and second mating edges 36, 38. The axial dimensions of the first and second mating edge impingement chambers 94, 96 are substantially greater than circumferential width dimensions of the first and second mating edge impingement chambers 94, 96 extending generally perpendicular to the first and second mating edges 36, 38.

It is noted that the trailing edge impingement chambers 82 and the first and second mating edge impingement chambers 94, 96 are not in fluid communication with one another, as illustrated in FIGS. 2 and 3. This is to promote desired amounts of cooling fluid to be provided to the respective cooling systems 70, 72, 74, as will be discussed herein. It is further noted that the trailing edge impingement chambers 82 (and the trailing edge discharge passages 84) and the first and second mating edge impingement chambers 94, 96 can be EDM drilled into the panel 30 to facilitate an advantageous manufacture of the ring segment 24. Still further, if it is desirable that cooling fluid not be able to escape out of the ends of the first and second mating edge impingement chambers 94, 96 these ends can be sealed closed, e.g., by a suitable weld plugging procedure.

The first and second mating edge impingement chambers 94, 96 are each associated with a plurality of corresponding metering discharge passages 98, 100. The metering discharge passages 98, 100 extend from the respective first and second mating edge impingement chambers 94, 96 to the corresponding mating edges 36, 38 of the panel 30 for discharging cooling fluid from the first and second mating edge impingement chambers 94, 96. As illustrated in FIGS. 2 and 3, the metering discharge passages 98, 100 may be angled toward the trailing edge 34 of the panel 30 to promote a flow of cooling fluid discharged from the metering discharge passages 98, 100 in a downstream direction, i.e., in the direction of the hot working gases passing through the hot gas flow path 20. Further, as illustrated in FIG. 4, the metering discharge passages 98, 100 may be angled slightly radially inwardly to discourage hot gas from flowing radially outwardly, i.e., by pushing the hot gas radially inwardly.

The panel 30 may include circumferential seal slots (not shown) along the leading and trailing edges 32, 34 for engaging circumferential seals (not shown) extending between the leading and trailing edges 32, 34 and respective edges of adjacent vane platforms 110, 112, see FIG. 1. The panel 30 may also include axial slots 114 (see FIG. 4) for engaging axial seals (not shown) extending to edges of adjacent ring segments (not shown).

During operation of the engine, cooling fluid may be supplied to the cooling fluid plenum 28 via the channel 56 formed in the blade ring carrier 26. The cooling fluid in the cooling fluid plenum 28 flows through the impingement holes 58 in the impingement tube 50 where the cooling fluid impinges on the outer side 40 of the panel 30 to provide impingement cooling to the outer side 40 of the panel 30. Portions of this cooling fluid pass into the metering supply passages 80, 90, 92 of the trailing edge cooling system 70 and the first and second mating edge cooling system 72, 74.

The portion of the cooling fluid passing into the metering supply passages 80 of the trailing edge cooling system 70 impinges on the respective portions of the panel 30 that define the trailing edge impingement chambers 82. Thereafter, this portion of the cooling fluid provides convective cooling to the panel 30 as it flows axially downstream through the trailing edge impingement chambers 82. The cooling fluid then exits the panel 30 through the trailing edge discharge passages 84. Upon exiting the trailing edge discharge passages 84, this portion of the cooling fluid may provide impingement cooling for the adjacent downstream vane platform 112 and then may be mixed with the hot working gas flowing through the hot gas flow path 20.

The portions of the cooling fluid passing into the metering supply passages 90, 92 of the first and second mating edge cooling system 72, 74 impinge on the respective portions of the panel 30 that define the first and second mating edge impingement chambers 94, 96. Thereafter, these portions of the cooling fluid exit the panel 30 through the respective first and second mating edge discharge passages 98, 100. These portions of the cooling fluid flow provide convective cooling to the panel 30 as they flow within the first and second mating edge impingement chambers 94, 96 and the first and second mating edge discharge passages 98, 100. Upon exiting the first and second mating edge discharge passages 98, 100, these portions of the cooling fluid may provide impingement cooling for the respective adjacent ring segments and then may provide a cooling air barrier to discourage hot working gases from flowing radially outwardly before being mixed with the hot working gas flowing through the hot gas flow path 20.

It is believed that the present configuration for the ring segment 24 provides an efficient cooling of the panel 30 via the impingement and convective cooling provided by the cooling fluid, and that the efficient cooling of the ring segment 24 may result in a lower cooling fluid requirement than prior art ring segments. Hence, enhanced cooling may be provided within the ring segment 24 while minimizing the volume of cooling fluid discharged from the ring segment 24 into the hot working gas, with an associated improvement in engine efficiency. Further, the distributed cooling provided to the panel 30 may improve the uniformity of temperature distribution across the ring segment 24, with an associated reduction in the metal temperature and reduction in thermal stress, resulting in an improved or extended life of the ring segment 24.

Further, the diameters of the metering supply passages 80, 90, 92 of the trailing edge cooling system 70 and the first and second mating edge cooling systems 72, 74 may be configured as to allow desired amounts of cooling fluid into the respective cooling systems 70, 72, 74. For example, it may be desirable to size the first and second mating edge metering supply passages 90, 92 relative to the trailing edge metering supply passages 80 such that adequate cooling fluid is provided into each of the cooling systems 70, 72, 74. Variables that may be considered are, for example, a pressure gradient that exists between the trailing edge 34 and the first and second mating edges 36, 38, and/or the number of metering supply passages 80, 90, 92 that are provided for the associated cooling system 70, 72, 74. For example, since the pressure at the trailing edge 34 is lower than pressures at the first and second mating edges 36, 38 during operation, larger first and second mating edge metering supply passages 90, 92 may be desirable. However, if the number of first and second mating edge metering supply passages 90, 92 is greater than the number of trailing edge metering supply passages 80, larger trailing edge metering supply passages 80 may be desirable. Moreover, it may be desirable that ones of the first and second mating edge metering supply passages 90, 92 closer to the leading edge 32 of the panel 30 be larger than ones of the first and second mating edge metering supply passages 90, 92 closer to the trailing edge 34. This could be due to a pressure gradient that exists between the leading edge 32 and the trailing edge 34 and/or a larger need for cooling fluid near the leading edge 32, i.e., due to higher working gas temperatures at the leading edge 32.

Moreover, as the cooling fluid associated with the first and second mating edge cooling systems 72, 74 is metered twice, i.e., a first time at the metering supply passages 90, 92 and a second time at the metering discharge passages 98, 100, amounts of cooling fluid provided to the first and second mating edge cooling systems 72, 74 are believed to be more accurately controlled.

Referring now to FIG. 5, a ring segment 224 according to another embodiment of the invention is illustrated. In this embodiment, structure similar to that described above with reference to FIGS. 1-4 includes the same reference number increased by 200. The ring segment 224 forms part of a seal structure in a turbine section of a turbine engine, as discussed above with reference to FIG. 1.

The ring segment 224 includes a panel 230 having side edges including a leading edge 232, a trailing edge 234, a first mating edge 236, and a second mating edge 238. The panel 230 further includes an outer side 240 and an inner side (not shown in this embodiment), wherein the inner side defines a corresponding portion of a hot gas flow path as discussed above. The panel 230 defines a structural body for the ring segment 224, and includes a plurality of front flanges or hook members 244 a and a plurality of rear flanges or hook members 244 b for mounting the ring segment 224 to a blade ring carrier (not shown in this embodiment) as discussed above.

In this embodiment, the ring segment 224 includes a trailing edge cooling system 270, a first mating edge cooling system 272, a second mating edge cooling system 274, and a leading edge cooling system 400 formed within the panel 230.

The trailing edge cooling system 270 comprises a plurality of metering supply passages 280 formed in a central recessed portion 260 of the panel 230. The metering supply passages 280 of the trailing edge cooling system 270 direct a portion of cooling fluid provided from a cooling fluid plenum (not shown in this embodiment) to the outer side 240 of the panel 230 into impingement chambers 282 of the trailing edge cooling system 270. As the cooling fluid enters the trailing edge impingement chambers 282 from the metering supply passages 280 it impinges on a surface of the panel 230 that defines the corresponding impingement chamber 282. As shown in FIG. 5, each impingement chamber 282 of the trailing edge cooling system 270 according to this embodiment includes a plurality of metering supply passages 280. Hence, the cooling fluid flowing through the impingement chambers 282 is replenished by cooling fluid along an axial length of the impingement chambers 282. Thus, although the cooling fluid is heated as it flows along the length of the impingement chambers 282, it does not experience overheating in that the impingement cooling fluid is supplied to the impingement chambers 282 at regular intervals to ensure cool fluid is available for convective cooling along the length of the impingement chambers 282.

As shown in FIG. 5, the trailing edge impingement chambers 282 comprise an elongated axial dimension extending parallel to the first and second mating edges 236, 238. The axial dimension of the impingement chambers 282 is substantially greater than a circumferential width dimension of the impingement chambers 282 extending generally perpendicular to the first and second mating edges 236, 238.

The trailing edge impingement chambers 282 are each associated with a corresponding discharge passage 284 of the trailing edge cooling system 270. The trailing edge discharge passages 284 extend from the respective trailing edge impingement chambers 282 to the trailing edge 234 of the panel 230 for discharging cooling fluid from the trailing edge impingement chambers 282.

The first and second mating edge cooling systems 272, 274 each comprise a plurality of metering supply passages 290, 292 formed in the central recessed portion 260 of the panel 230 in this embodiment. The metering supply passages 290 of the first mating edge cooling system 272 in the embodiment shown are located toward the first mating edge 236 of the panel 230 and direct a portion of the cooling fluid provided from the cooling fluid plenum to the outer side 240 of the panel 230 into a plurality of impingement chambers 294 of the first mating edge cooling system 272. The metering supply passages 292 of the second mating edge cooling system 274 in the embodiment shown are located toward the second mating edge 238 of the panel 230 and direct a portion of the cooling fluid provided from the cooling fluid plenum to the outer side 240 of the panel 230 into a plurality of impingement chambers 296 of the second mating edge cooling system 274.

As the cooling fluid enters the first and second mating edge impingement chambers 294, 296 through the metering supply passages 290, 292 it impinges on respective surfaces of the panel 230 that define the corresponding first and second mating edge impingement chambers 294, 296. The metering supply passages 290, 292 provide impingement cooling fluid across areas of the panel 230 near the respective first and second mating edges 236, 238 of the panel 230. While the first and second mating edge impingement chambers 294, 296 are illustrated in FIG. 5 as comprising a plurality of individual chambers, additional or fewer first and second mating edge impingement chambers 294, 296 could be provided.

The first and second mating edge impingement chambers 294, 296 are each associated with a plurality of corresponding metering discharge passages 298, 300. The metering discharge passages 298, 300 extend from the first and second mating edge impingement chambers 294, 296 to the respective mating edges 236, 238 of the panel 230 for discharging cooling fluid from the first and second mating edge impingement chambers 294, 296. As illustrated in FIG. 5, at least one of the metering discharge passages 298A, 300A of the axially foremost mating edge impingement chambers 294, 296 may be angled toward the leading edge 232 of the panel 230 to provide cooling fluid to the leading edge 232. Further illustrated in FIG. 5, at least one of the metering discharge passages 298B, 300B of the axially aftmost mating edge impingement chambers 294, 296 may be angled toward the trailing edge 234 of the panel 230 to provide cooling fluid to the trailing edge 234. Although the first and second mating edge impingement chambers 294, 296 in the embodiment shown in FIG. 5 each include two or more metering discharge passages 298, 300, additional or fewer metering discharge passages 298, 300 could be provided for each first and second mating edge impingement chamber 294, 296.

The leading edge cooling system 400 comprises a plurality of metering supply passages 402 formed in the central recessed portion 260 of the panel 230. The metering supply passages 402 of the leading edge cooling system 400 in the embodiment shown are located toward the leading edge 232 of the panel 230 and direct a portion of the cooling fluid provided from the cooling fluid plenum to the outer side 240 of the panel 230 into a plurality of impingement chambers 404 of the leading edge cooling system 400. As the cooling fluid enters the leading edge impingement chambers 404 through the respective metering supply passages 402 it impinges on respective surfaces of the panel 230 that define the corresponding leading edge impingement chambers 404 such that the metering supply passages 402 provide impingement cooling fluid across an area of the panel 230 near the leading edge 232 of the panel 230. While the leading edge impingement chambers 404 are illustrated in FIG. 5 as comprising a plurality of individual chambers, additional or fewer leading edge impingement chambers 404 could be provided.

The leading edge impingement chambers 404 are each associated with a plurality of corresponding metering discharge passages 406. The metering discharge passages 406 extend from the leading edge impingement chambers 404 to the leading edge 232 of the panel 230 for discharging cooling fluid from the leading edge impingement chambers 404.

It is noted that the trailing edge impingement chambers 282, the first and second mating edge impingement chambers 294, 296, and the leading edge impingement chambers 404 are not in fluid communication with one another, as illustrated in FIG. 5. This is to promote desired amounts of cooling fluid to be provided to the respective cooling systems 270, 272, 274, 400. Further, diameters of the metering supply passages 280, 290, 292, 402 of the respective cooling systems 270, 272, 274, 400 can be sized to provide desired amounts of cooling fluid into the respective impingement chambers 282, 294, 296, 404. As one example, it may be desirable that diameters of the leading edge metering supply passages 402 be larger than diameters of the trailing edge metering supply passages 280 due to the pressure gradient that exists between the leading edge 232 and the trailing edge 234 of the panel 230.

It is further noted that the trailing edge impingement chambers 282 (and the trailing edge discharge passages 284) and the leading edge discharge passages 406 can be EDM drilled into the panel 230 to facilitate an advantageous manufacture of the ring segment 224.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention. 

1. A ring segment for a gas turbine engine comprising: a panel having a leading edge, a trailing edge, a first mating edge, a second mating edge, an outer side, and an inner side, wherein cooling fluid is provided to said outer side and said inner side defines at least a portion of a hot gas flow path through the gas turbine engine; a first mating edge cooling system within said panel that receives a portion of the cooling fluid provided to said outer side of said panel for cooling said panel at one of said first and second mating edges, said first mating edge cooling system comprising at least one first mating edge impingement chamber, each first mating edge impingement chamber including: at least one metering supply passage extending from said outer side of said panel to said first mating edge impingement chamber, wherein cooling fluid impinges on a surface of said panel defining said first mating edge impingement chamber as it flows into said first mating edge impingement chamber through said at least one metering supply passage; and at least one metering discharge passage that extends from said first mating edge impingement chamber to said one of said first and second mating edges of said panel.
 2. The ring segment of claim 1, further comprising a second mating edge cooling system within said panel that receives a portion of the cooling fluid provided to said outer side of said panel for cooling said panel at the other of said first and second mating edges, said second mating edge cooling system comprising at least one second mating edge impingement chamber, each second mating edge impingement chamber including: at least one metering supply passage extending from said outer side of said panel to said second mating edge impingement chamber, wherein cooling fluid impinges on a surface of said panel defining said second mating edge impingement chamber as it flows into said second mating edge impingement chamber through said at least one metering supply passage; and at least one metering discharge passage that extends from said second mating edge impingement chamber to the other of said first and second mating edges of said panel.
 3. The ring segment of claim 2, further comprising a trailing edge cooling system within said panel that receives a portion of the cooling fluid provided to said outer side of said panel for cooling said panel at said trailing edge, said trailing edge cooling system comprising at least one trailing edge impingement chamber, each trailing edge impingement chamber including: at least one supply passage extending from said outer side of said panel to said trailing edge impingement chamber; and at least one discharge passage that extends from said trailing edge impingement chamber to said trailing edge of said panel.
 4. The ring segment of claim 3, wherein said impingement chambers of said trailing edge cooling system and said first and second mating edge cooling systems are not in fluid communication with one another.
 5. The ring segment of claim 3, further comprising a leading edge cooling system within said panel that receives a portion of the cooling fluid provided to said outer side of said panel for cooling said panel at said leading edge, said leading edge cooling system comprising at least one leading edge impingement chamber, each leading edge impingement chamber including: at least one supply passage extending from said outer side of said panel to said leading edge impingement chamber; and at least one discharge passage that extends from said leading edge impingement chamber to said leading edge of said panel.
 6. The ring segment of claim 5, wherein said supply passages of said leading edge cooling system and said trailing edge cooling system comprise metering supply passages, wherein said metering supply passages of said leading edge cooling system include diameters that are larger than diameters of said metering supply passages of said trailing edge cooling system.
 7. The ring segment of claim 1, wherein said at least one first mating edge impingement chamber comprising a single first mating edge impingement chamber extending from near said leading edge to near said trailing edge of said panel.
 8. The ring segment of claim 1, further comprising an impingement tube located radially outwardly from said panel, said impingement tube comprising a plurality of impingement holes, wherein the cooling fluid that is provided to said outer side of said panel passes through said impingement holes in said impingement tube and impinges on said outer side of said panel.
 9. A ring segment for a gas turbine engine comprising: a panel having side edges comprising a leading edge, a trailing edge, a first mating edge, and a second mating edge, said panel further including an outer side, and an inner side, wherein cooling fluid is provided to said outer side, and said inner side defines at least a portion of a hot gas flow path through the gas turbine engine; a central recessed portion defining a recessed surface formed in said outer side and surrounded by a rim portion comprising an unrecessed portion extending around an outer periphery of the recessed portion along each of said side edges; recess portion walls defining said outer periphery of said recessed portion, each said recess portion wall extending radially between said recessed surface and said unrecessed portion; and at least one impingement chamber located in said panel, said at least one impingement chamber including: at least one metering supply passage extending from said outer side for passage of cooling fluid into said impingement chamber to impinge on and cool a surface of said impingement chamber; and at least one metering discharge passage extending from said impingement chamber to one of said side edges for passage of cooling fluid from said impingement chamber to said one side edge.
 10. The ring segment of claim 9, wherein said at least one impingement chamber comprises an elongated dimension extending parallel to said one side edge that is substantially greater than a width dimension extending generally perpendicular to said one side edge.
 11. The ring segment of claim 10, wherein said at least one metering supply passage comprises a plurality of metering supply passages located along said elongated dimension of said at least one impingement chamber.
 12. The ring segment of claim 11, wherein said at least one impingement chamber comprises a plurality of impingement chambers located along said one edge.
 13. The ring segment of claim 11, wherein said at least one metering discharge passage comprises a plurality of metering discharge passages located along said elongated dimension of said at least one impingement chamber.
 14. The ring segment of claim 13, wherein said at least one impingement chamber comprises a plurality of said impingement chambers located along both said first and second mating edges.
 15. The ring segment of claim 14, wherein: said impingement chambers are EDM drilled into said panel from one of said leading edge and said trailing edge of said panel; and openings of said impingement chambers at said one of said leading edge and said trailing edge are sealed to effect a discharge of cooling fluid from said impingement chambers only through said metering discharge passages.
 16. The ring segment of claim 9, wherein said at least one impingement chamber is located in said panel between at least one of said recess portion walls and one of said mating edges.
 17. The ring segment of claim 9, further comprising a trailing edge cooling system comprising a plurality of circumferentially spaced apart impingement chambers having an elongated dimension extending parallel to said mating edges and located between said recessed surface and said inner side, each said impingement chamber of said trailing edge cooling system including: at least one metering supply passage extending from said recessed surface to said impingement chamber for passage of cooling fluid into said impingement chamber to impinge on and cool a surface of said impingement chamber; and a discharge passage extending from said impingement chamber to said trailing edge for passage of cooling fluid from said impingement chamber to said trailing edge.
 18. The ring segment of claim 17, wherein: at least one metering supply passage of at least one of said impingement chambers of said trailing edge cooling system is located near said leading edge; and said discharge passage of said at least one impingement chamber of said trailing edge cooling system is located at said trailing edge.
 19. The ring segment of claim 9, wherein said at least one impingement chamber comprising a single impingement chamber extending from near said leading edge to near said trailing edge of said panel. 